The present disclosure relates generally to the manufacturing of semiconductor devices, and more particularly to a photolithography process in semiconductor manufacturing.
During the manufacturing of semiconductor devices, one of the requirements is a suitable depth of focus (DOF) window. Generally, an effective DOF covers all the variations of the photoresist thickness, local substrate topology step height, and wafer center and edge step height differences. It is desired that a semiconductor device be manufactured within the desired critical dimension (CD) specification without scum or top loss defects.
As the sizes of semiconductor devices continue to decrease, semiconductor manufacturers strive to devise photolithography processes that accommodate the needs of customers.